Cooling of cement clinker



Sept. 19, 1939. E. RQNNE COOLING 0F CEMENT CLINKER U Filed Jan. 18, 19592 Sheets-Sheet 1 lNV TOR ATTORNEY;

Spt. 19, 1939. RQNNE COOLING OF CEMENT CLINKER Filed Jan. 18; 19:59

2 Sheets-Sheet 2 ATTORNEY;

mytmaterials. 1 3

Patented Sept. 19, v

Elna: mimic, cope This invention relates the production-of cer .ment andis concerned more'partlcularly with the cooling of cement clinker burnedin a rotary kiln. u In the manufacture of cement, it is now known -51that if the-hot clinker -ls suddenly cooled, shortly .aftcr .itsformatlon;' frompthe temperature at .cvwwhich. the clinkring ,tookplaceto a value of Z from 1'1009J 'C.{(20 128F.)'to 1200' C. (2192 F.),thez-cement madejfrom the clinker has improved rink-properties, and," inparticu1ar-,f'unsoundness is eliminated or 'greatly reduced. Suchrapidcoolingor chilling is especially important in connec- .tion withclinker-made from raw materials rel- 1 'atively high in magnesia andalso aflords advan- 15 tages in the -production of cement from other Thepresent invention is directed to the provision of a novel method andapparatusby which rapid cooling: or chilling of cement clinker.zuathrough thetemperature range above mentioned 1 :can be convenientlyand economically effected.

According to the'invention, the chilling is ac- :complished bycontinuously adding to the hot clinker issuing from the burning zone inthe 25 kiln clinker which has been cooled, the additions being made atsuch a rate in relation to the temperatures of the hot and cooledclinkers that the desired result is obtained.

i .In the practiseof the invention, circulation of 30 some of theclinker: from the kiln may be advantageously employed, and in suchprocedure, the clinker discharging from the kiln is passed through acooler in the usual way and a part of the cooled material is thenreturned to the so kiln at thedesired point. The cooler used for thepurpose may take various forms, as, for example, it may be whollyseparate from the kiln or be formedas an extension of the kiln or consst of a plurality of cooling chambers mounted 40 longitudinally ofthe'kiln on the outside thereof. 7

Means are then provided for returning a part of the cooled clinkerftothe kiln at the desired point, the construction used for this purposedepending on that of the cooler employed. 1

For .a better understanding of the invention, reference may be had tothe accompanying drawings in which Fig. 1 is a view partly inlongitudinal section and partly in elevation of one form of apparatussuitable for the practice of the process of the invention;

Figs. 2, 3, and 4 are sectional views on the lines 2-2, 3-3, and, 4-4,respectively, of Fig. 1; 55 Fig. .5 is a longitudinal sectional view ofan- STATES PATIENT OFFICE :Denmark; assignor to F. L. Smidth Jr 00., NewYork N. Y., a corporation of New Jersey Application January 18, 1939,Serial No. 251,622 I In Great Britain January 18, 1938.

19 Claims. (01. ass-+53) other form' of apparatus suitable for thepractice of the process of the invention; and

Figs. 6 and '7 are sectional views on the lines 66 and 'II,respectively, of Fig. 5.

The apparatus shown in Fig. 1 includes a rotary kiln ill of generallystandard construction having a refractory lining II with an internal daml2, this dam being slightly beyond the end of the burning zone. Thekiln'has the usual circumfrential tires l3 resting upon rollers l4 and10 is rotated by any suitable means. The lower end of the kiln is closedby the conventional clo-' sure means l5 and thefuel for heating the kilnis supplied through a burner pipe I6 projecting into the kiln throughthe closure.

In the construction illustrated, the cooler takes the form of aplurality of cooling chambers ll of generally cylindrical form, thechambers being mounted longitudinally of the kiln on the outside thereofand connected to the interior of the kiln near its lower end by conduitsl8. At their lower ends, the cooling chambers have end plates l8 and areprovided with spouts 20, the arrangement being such that the clinker tobe discharged enters a spout and passes therefrom when the chamber fromwhich-the spout leads is in an upper position, as illustrated in Fig. 2.Mounted at the ends of the cooling chambers is a hood 2| through whichthe ends of the cooling chambers with'their spouts may freely move, anda hopper 22 lies within the hood in position to receive clinkerdischarged from the spouts 20. From the bottom of the hopper leadsaconduit 23 for conducting the discharged clinker away .to

, any suitable delivery point.

of the opening being varied by means of a plate 40 26 adjustably securedto the chamber wall. Cooled clinker passing from the chamber through theopening enters the casing and moves through the later as the chamber iscarried around during rotation of the kiln. A conduit 21 leads from theend of the casing and extends around the kiln helically to a pointupward from the dam l2, where the conduit is in communication with theinterior of the kiln through an opening 28 through the kiln shell andlining.

With the construction described, hot clinker is discharged from the kilnthrough the passages l8 and enters the chambers l'l through which it isadvanced by gravity'as the kiln rotates. Air drawn counter-currentthrough the chambers and into the kiln through the passages l3 cools theadvancing clinker, until by the time the clinker has reached the lowerends of the chambers, its temperature has fallen within the range fromabout 50 C. (122 F.) to 200 0. (392 F.). A part of the clinker cooled ineach or the chambers from which a conduit 21 leads enters the conduitthrough casing 24, and is advanced along the conduit by rotation of thekiln until it is discharged into the kiln through the opening 28. Theamount of cooled clinker thus returned may be controlled by varying thesizes of the openings 25 from the chambers and the amount is soregulated that the returned cooled clinker is effective to chill the hotclinker issuing from the burning zone to a temperature of from 1100 C.(2012 F.) to 1200 C. (2192 F.) This chilling action occurs with suchrapidity as to impart to the cement made from the clinker the desirablecharacteristics to which reference has been made above. The remainder ofthe cooled clinker from those chambers provided with conduits 21 andfrom the other chambers in the series is delivered into hopper 22 and isthence conducted through conduit 23 to the desired point.

In the construction shown in Fig. 5, the kiln 291s provided with theusual refractory lining 30 formed with the internal dam 3| and the lowerend of the kiln has the usual closure 32 through which extends theburner pipe 33. Thekiln is provided with tires 34 resting on rollers 35and is rotated by means not shown. Mounted longitudinally of the kiln onthe outside thereof are cooling chambers 36 connected at their lowerends to the interior of the kiln beyond the dam 3| by passages 31.Within the chambers are screw flights 38 so arranged that, as the kilnrotates, the hot clinker entering the chambers through the passages ismoved upward through the chambers. The upper ends of the chambers areopen and passages 39 lead from the curved walls of certain of thechambers near the open ends to the interior of the kiln at a point justbeyond the buming zone.

Flow of air through the passages 39 and into the kiln is prevented bypivotally mounted countor-weighted plates 40, the plates being providedwith cranks 4| on the outside of the passages positioned to engage a camrail 42. The arrangement of the rail is such that the plates are movedto open position only when the ends of the passages lie below the massof hot clinker 43 within the kiln, and throughout the remainder of therevolution of the chambers from which passages lead, the plates preventflow of air through the passages. The clinker in the several chambers,which -.is not discharged through the passages, leaves through the openends of the chambers and falls into a hopper 44 from which it isconducted away to a suitable delivery point.

In the operation of the apparatus shown in Figs. 5 to 7, all of the hotclinker issuing from the kiln enters the cooling chambers and is ad-'vanced' through these chambers as the kiln rotates. In this movement,the clinker is cooled by air drawn into the kiln through the chambers. Aportion of the cooled clinker leaving the chambers is then returned tothe kiln to chill the hot clinker issuing from the burning zone, and theremainder of the cooled clinker is delivered to the desired storage orother point. In the constructions of both Figs. 1 and 5, the air whichhas been used for cooling the clinker is drawn into the kiln where ittakes part in the combustion with the fuel. In the Fig. 1 construction,little or no air can enter the kiln except after having passedlengthwise through the chambers, and in the Fig. 5 construction, shortcircuiting oi the chambers by the air streams is prevented by thepivoted plates in the passages 39.

I claim:

1. A method of cooling cement clinker produced in a rotary kiln, whichcomprises adding cooled clinker to that in the kiln at a point beyondthe clinkering zone.

2. A method of cooling cement clinker produced in a, rotary kiln, whichcomprises cooling the clinker discharged from the kiln, and returning aportion of the cooled clinker to the kiln at a point adjacent theclinkering zone to be mixed with the hot clinker leaving said zone.

3. A method of cooling cement clinker produced in a rotary kiln, whichcomprises cooling the clinker discharged from the kiln, returning aportion of the cooled clinker to the kiln at a point beyond theclinkering zone to be mixed with the hot clinker leaving the zone andregulating the amount of the cooled clinker returned to insure that itwill eifect rapid cooling of the hot clinker to a temperature belowabout 2200 F.

4. A method of cooling cement clinker produced in a rotary kiln, whichcomprises cooling the clinker discharged from the kiln by passing airover it, returning a portion of the cooled clinker to the kiln at apoint beyond the clinkering zone to be mixed with the hot clinkerleaving the zone, and passing the air heated by its contact with theclinker into the kiln for use in the combustion of the fuel to effectthe clinkering.

5. A method of cooling cement clinker produced in a rotary kiln, whichcomprises cooling the clinker discharged from the kiln, subdividing thecooled clinker and delivering one portion to storage, and returning theother portion to the kiln at a point beyond the clinkering zone to bemixed with the hot clinker leaving the zone.

6. An apparatus for producing cement which comprises a rotary kiln,means for heating the interior of the kiln, means receiving hot clinkerdischarging from the kiln and cooling it, and means for returning aportion. of the cooled clinker from the cooling means to the kiln at apoint beyond the clinkering zone to be mixed with the hot clinkerissuing from said zone.

7. An apparatus for producing cement which comprises a rotary kiln,means rotatable with the kiln for receiving hot clinker discharging fromthe kiln and cooling it, and means for returning a part of the cooledclinker from the cooling means to the kiln at a point beyond theclinkering zone.

8. An apparatus for producing cement which comprises a rotary kiln, acooling chamber connected to the kiln and receiving hot clinkerdischarging therefrom, means for returning a portion of the cooledclinker from the cooling chamber to the kiln at a point beyond theclinkering zone, and means for conducting away the remainder of thecooled clinker from the chamber.

9. An apparatus for producing cement which comprises a rotary kiln, aplurality of cooling chambers connected to the kiln and receiving hotclinker discharging therefrom, means for returning clinker that has beencooled in certain of the chambers to the kiln at a point beyond theclinkering zone, and means for conducting away the clinker that has beencooled in the remainder of the chambers.

10. An apparatus for producing cement which comprises a rotary kiln, aplurality of cooling 75 chambers mounted on the outside of the kiln torevolve therewith, said chambers receiving clinker discharging from thekiln, means for returning to the kiln at a point beyond the clinkeringzone a part of the clinker cooled'in the chambers, and means forconducting away the remainder of the cooled clinker. I

11. An apparatus for producing cement which comprises a rotary kiln, acooling chamber secured to the kiln to move therewith, the interior ofthe chamber being connected to the interior of the kiln to receive hotclinker issuing therefrom, the clinker passing through and out of thechamber as the kiln rotates, and a passage receiving cooled clinker fromthe discharge endof the chamber and returning it to the kiln at a pointbeyond the clinkering zone.

clinkering zone, and means for regulating the quantity of cooled clinkerentering the passage. 13. An apparatus for producing cement whichcomprises an inclined rotary kiln, a plurality of cooling chambersmounted longitudinally of the kiln on .theoutside thereof and receivinghct clinker discharging from the kiln, the clinker passing downwardthrough the chambers as the kiln rotates and being cooled, and helicalconduits mounted on the outside of the kiln and receiving *oled clinkerfrom certain of the chambers and deli zring the clinker into the kilnbeyond the clinke1 ing zone as the kiln rotates.

14. An apparatus for producing cement which comprises an inclined rotarykiln, a plurality of cooling chambers mounted longitudinally of the kilnon the outside thereof, passages connecting the upper end of eachchamber to the interior of the kiln, the hot clinker from the kilnentering the chambers through the passages and moving downward throughthe chambers to the lower end thereof as the kiln rotates, helicalconduits mounted'on the outside of the kiln and leading from the lowerends of certain of the chambers to the interior of the kiln at a pointbeyond the burning zone, the conduits receiving cooled clinker andreturning it to the kiln, and means for receiving cooled clinker fromtheother chambers.

15. An apparatus for producing cement which comprises an inclined rotarykiln, a plurality of cooling chambers mounted longitudinally of the kilnon the outside thereof, passages connecting the upper end of eachchamber to the interior of the kiln, the hot clinker from the kilnentering the chambers through the passages and moving downward throughthe chambers to the lower end thereof as the kiln rotates; helicalconduits ker and returning it to the kiln, means for regv ulating theamount of clinker entering the conduits from the chambers from whichthey lead, the remainder of the cooled clinker from said chambers andfrom the remaining chambers being discharged, and means for receivingthe cooled clinker discharged from the chambers.

16. -An apparatus for producing cement which comprises an inclinedrotary kiln, a chamber mounted longitudinally of the kiln on the outsidethereof, a passage leading from the interior of the kiln to the lowerend of the chamber, hot clinker leaving the kiln through the passage andentering the chamber, means in the chamber for moving the clinker upwardthrough the chamber as the kiln rotates, and a passage leading from theupper end of the chamber to the interior of the kiln at a point beyondthe burning zone.

17. An apparatus for producing cement which comprises an inclined rotarykiln, a chamber mounted longitudinally of the kiln on the outsidethereof, a passage leading from the interior of the kiln to the lowerend of the chamber, hot clinker leaving the kiln through the passage andentering the chamber, means in the chamber for movingthe clinker upwardthrough the chamber as the kiln rotates, a passage leading from theupper end of the chamberto the interior of the through the chambers asthe kiln rotates and being cooled, means at the lower ends of thechambers for permitting discharge from the chambers when they are in anupper position during rotation of the kiln, means for receiving cooledclinker discharged from the chambers, and means for receiving cooledclinker from certain of the chambers and returning it to the interior ofthe kiln beyond the burning zone.

19. An apparatus for producing cement which comprises a rotary kiln, aplurality of cooling chambers mounted longitudinally of the kiln on theoutside thereof, the chambers having open upper ends, passagesleading'from the kiln to the lower ends of the chambers, hot clinkerentering' the chambers through the passages as the kiln rotates, meansin the chambers for moving the clinker upward through the chambers asthe kiln rotates, discharge passages connecting certain of the chambersnear their upper ends with the kiln at a point beyond the burning zone,means for keeping the discharge passages closed throughout the majorportion of the path of revolution of the chambers from which thepassages lead.

and means for receiving cooled clinker discharged 5 from the open endsof the chambers.

EINAR mam.

